Painful Swelling Research Articles

In situ size amplification strategy reduces lymphatic clearance for enhanced arthritis therapy

Rheumatoid arthritis (RA) is an autoimmune disorder characterized by painful swelling and inflammation, arising from the immune system attacking on healthy cells. However, arthritic sites often experience increased lymph flow, hastening drug clearance and potentially reducing treatment effectiveness. To address this challenge, an in situ size amplification has been proposed to reduce lymphatic clearance and thereby enhance arthritis therapy. This system has been developed based on a conjugate of dexamethasone (Dex) and polysialic acid (PSA), linked via an acid-sensitive linker, supplemented with bis-5-hydroxytryptamine (Bis-5HT) on the PSA backbone. Under physiological conditions, the system autonomously assembles into stable nanoparticles (PD5NPs), facilitating prolonged circulation and targeted delivery to inflamed joints. Upon arrival at arthritic joints, Bis-5HT reacts to elevated myeloperoxidase (MPO) levels and oxidative stress, prompting particle aggregation and in-situ size amplification. This in situ size amplification nanocarrier effectively reduces lymphatic clearance and serves as reservoirs for sustained Dex release in acidic pH environments within arthritic sites, thus continuously alleviating RA symptoms. Moreover, investigation on the underlying mechanism elucidates how the in situ size amplification nanocarrier influences the transportation of PD5NPs from inflamed joints to lymphatic vessels. Our study offers valuable insights for optimizing nanomedicine performance in vivo and augmenting therapeutic efficacy.Graphical

A rare case of limited granulomatosis with polyangiitis presenting as bilateral parotitis

Background: Granulomatosis with polyangiitis (GPA) is a rare autoimmune vasculitis affecting small and medium-sized vessels, commonly involving the respiratory tract and kidneys. Salivary gland involvement, particularly bilateral parotitis, is an uncommon presentation of GPA. Case Report: We report the case of a 38-year-old Asian male who presented with left ear pain and parotid swelling after a water park visit. Initially treated with antibiotics for suspected otitis externa, his symptoms worsened, leading to bilateral parotitis, facial palsy, and otomastoiditis. Imaging revealed parotid abscesses and lab results showed elevated antineutrophil cytoplasmic antibodies (ANCA), specifically cytoplasmic ANCA directed against proteinase 3, confirming the diagnosis of GPA. Cultures and autoimmune workups for other causes, such as Sjogren’s syndrome and immunoglobulin G4-related disease, were negative. Treatment with high-dose corticosteroids and methotrexate resulted in significant clinical improvement. Conclusion: This case highlights the importance of considering GPA in atypical presentations such as parotitis, even in the absence of renal involvement. Early diagnosis and appropriate immunosuppressive therapy are critical to prevent further complications in multisystem involvement.

Pseudoaneurysms of lower limb of orthopaedic traumatological origin: a literature review and our experience of 18 cases.

Arterial pseudoaneurysm is a rare yet potentially life-threatening complication that can arise as a late sequelae of penetrating injuries or orthopaedic procedures. We aim at sharing our institutional experience of managing 18 cases of lower limb arterial pseudoaneurysms in orthopaedic practice and to provide technical tips for emergency management of severe bleeding. A comprehensive literature review resulting from fractures and orthopaedic surgeries is also presented. The study group consisted mainly of male patients with a mean age of 48.5years. The mean duration between injury and pseudoaneurysm diagnosis was 86.7days. CT angiography and USG Doppler were the main diagnostic modality. Among the cases, five resulted from fracture fragments and 13 from iatrogenic injuries. Surgical interventions varied based on the artery involved and included excision and ligation, bypass grafting with dacron or vein graft, primary repair, and amputation in two cases. Complications included one patient with blowout at the anastomotic site and another case of deep infection. The literature review encompassed 108 cases of pseudoaneurysm of lower limb associated with fractures and iatrogenic injuries during orthopaedic procedures. Clinical manifestations varied widely which included painful swelling, pulsatility, bleeding, and neurological deficits. CT angiography was the most utilized diagnostic modality, while therapeutic embolization was the most common treatment method. Iatrogenic arterial injuries contributed to more than 60% of the cases as per the literature review. The most frequent mechanisms related to instrumentation were the placement of the third and fourth screws of the DHS plate, and the distal screw of a short nail in treating pertrochanteric fractures. This can be avoided by external rotation and abduction of the limb during distal screw insertion. A high index of clinical suspicion is needed especially when bleeding from the hardware site is noted. A swelling in the previously operated site should raise a suspicion of pseudoaneurysm and incision and drainage must be avoided without further imaging (Duplex USG or CT angiography). This study highlights the importance of cautious surgical techniques to minimize the occurrence of vascular injuries during orthopaedic surgeries.

A Solitary Osteochondroma Originating from the Spinous Process of the Third Cervical Vertebra: A Case Report and Comprehensive Literature Review

Background Osteochondroma is one of the most common solitary bone lesions. Multiple lesions are possible only in some genetic abnormalities, such as hereditary multiple exostoses (HME). Half of spinal osteochondroma is documented at the cervical level, although there are some levels and locations where it is rare to find an osteochondroma. Methods An advanced search of the PubMed database was performed for case reports and case series of spinal cervical osteochondroma. After data extraction, information was organized in one table and many figures to facilitate data comprehension. Result Osteochondroma was common in younger patients, with 26% of all cases in the literature being in those aged 18 to 35 years, and 24% of patients were aged 36 to 50. Over half (55%) of cases were in males. The most common presentation among all patients was neck pain and swelling or lump sensation. Moreover, 38% of cases were osteochondroma at the C1 level, and 33% were noted to affect the posterior arch. The majority of the cases had a favorable prognosis as most of them underwent total surgical resection of the tumor and decompression of the neural compartment. Conclusion Solitary cervical osteochondroma is a bony, benign lesion that can have devastating sequelae such as severe painful radiculopathy and quadriplegia if it is not approached correctly. History, examination, and radiological investigation are all crucial to making the best clinical judgment for the patients.

A 68-Year-Old Male with Giant Urethral Diverticulum Stone

Introduction: Urolithiasis primarily affects the kidneys, ureters, or bladder, but urethral stones are rare, making up less than 1% of all urinary tract stones. Their prevalence is 0.3% to 2%, with a higher incidence in men due to the longer male urethra. Symptoms range from asymptomatic to severe pain, dysuria, and urinary retention, often complicated by fever or renal failure. Urethral diverticulum, a rare malformation, can cause recurrent infections and stone formation. Diagnosis involves imaging, urethrography, and cystourethroscopy, while treatment depends on stone size and location. Delayed diagnosis can lead to significant morbidity. Case Presentation: A 68-year-old male presented to the clinic with a painful lump in the left scrotum, which had progressively enlarged and hardened. He reported experiencing painful, incomplete urination along with right-sided back pain. The patient had a history of similar lumps that had been surgically removed. Upon examination, a tender, hard mass measuring 4x3 cm was found in the left scrotum. Urethrography revealed a solitary opaque stone in the posterior urethra, while post-contrast imaging confirmed diverticulolithiasis in the bulbo-cavernous urethra, leading to stenosis and partial obstruction, confirming urethral obstruction due to stones. Laboratory tests returned normal results. Conclusion: Urethral stones are rare, constituting less than 1% of urinary tract stones, mainly affecting men. Symptoms range from asymptomatic to severe pain, with potential complications like fever and kidney failure. Diagnosis involves imaging, and timely management is crucial to prevent morbidity.

BMP-9 mediates fibroproliferation in fibrodysplasia ossificans progressiva through TGF-β signaling.

Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disorder presenting with progressive heterotopic ossification (HO) in soft tissues. Early-stage FOP is characterized by recurrent episodes of painful tissue swelling (flare-ups), with numerous proliferation-activated mesenchymal stromal cells (MSCs) subsequently causing HO. However, the mechanisms underlying flare-up progression remain unclear. In this study, we evaluated the proliferation of MSCs obtained from FOP patient-derived induced pluripotent stem cells (FOP-iPSCs) to elucidate the mechanisms underlying flare-ups and found that bone morphogenetic protein (BMP)-9 mediated enhanced proliferation by abnormal activation of transforming growth factor (TGF)-β signaling pathway in MSCs from FOP-iPSCs. In FOP model mice, elevated BMP-9 levels correlated with elevated phosphorylation of SMAD2/3 and increased cellular proliferation in the affected tissues, while systemic BMP-9 neutralization and knockout mitigated flare-ups and HO. Thus, BMP-9 aberrantly transduces TGF-β signaling and induces fibroproliferation, initiating flare-ups. This study provides novel insights into the development of future FOP therapies.

Perinatal Testicular Torsion : About A Clinical Case in the Pediatric Surgery Department of CHU Gabriel TOURE

Introduction : Perinatal testicular torsion is a rare pathology, occurring in utero and during the first month of life. We report a case of testicular torsion noted at birth, which allowed us to conduct a literature review. Observation :This was a male newborn, born at 38 weeks of amenorrhea, 2 prenatal consultations carried out and no prenatal assessment carried out. Admitted to the neonatology department for painful right scrotal swelling noted in the delivery room. The clinical examination revealed a good general impression, a recoloring time of less than 3 s. His archaic reflexes were present. He had a bluish right scrotal swelling, hard with the right testicle raised relative to the left side, non-transluminal, and painful on palpation. Scrotal ultrasound revealed a strangulated right inguinoscrotal hernia with pain in the herniated loops that were poorly vascularized on Doppler. The biological assessment came back normal. He underwent surgery. Exploration finds testicular torsion with necrosis. We performed an orchiectomy. The postoperative course was simple. Conclusion : Perinatal testicular torsion is a surgical emergency, the functional prognosis of the testicle is often poor.

Unusual Presentation of Oral DLBCL Resembling a Canine Fossa Abscess.

This report aims to describe a unique case of diffuse large B-cell lymphoma originating from the oral cavity, which presented with symptoms mimicking a canine fossa abscess. It emphasizes the importance of accurate differential diagnosis and appropriate treatment. A 64-year-old female patient visited the authors' clinic with a painful swelling in the left anterior region of the maxilla, persisting for 1 month. Initially, an abscess drainage procedure was performed, accompanied by extraction of the maxillary left canine and parenteral antibiotherapy. However, no improvement was observed during the follow-up appointment after 3 days. An incisional biopsy was then conducted under local anesthesia, leading to a histopathologic diagnosis of diffuse large B-cell lymphoma. The patient is currently under the care of the hematology department and receiving maintenance chemotherapy. Lymphomas occurring in the oral cavity are uncommon and may exhibit non-specific clinical features that resemble benign oral and dental conditions. Therefore, a comprehensive clinical evaluation is necessary to achieve an early and accurate diagnosis, with histopathologic examination being essential for suspicious lesions.

Uncommon association of tuberculosis with deep vein thrombosis in a child: a case report

Tuberculosis (TB) is a major global health issue, particularly in developing countries. While TB commonly affects the lungs, it can spread to nearly any organ system, leading to a range of complications. One rare extrapulmonary manifestation of TB is deep vein thrombosis (DVT), which is even more rarely reported in children. We report a case of a 13-year-old girl with progressive, painful swelling in right lower limb, accompanied by fever, cough and lymphadenopathy. Diagnostic imaging identified DVT in the right external iliac vein. Further investigation confirmed Mycobacterium tuberculosis infection. She was treated with anti-tubercular medication and therapeutic anticoagulation. Although uncommon, this case underscores the importance of recognizing this serious complication and need for timely diagnosis and treatment.

Mandibular Actinomyces Osteitis Associated with Florid Cemento-Osseous Dysplasia

Introduction: Actinomycosis is a rare chronic suppurative granulomatous infection caused by actinomyces. The Florid cemento-osseous dysplasia (FCOD) is a benign fibro-osseous lesion. We report a case of simultaneous association of these two entities with the use of PRF for the first time in this context. Case Report: A 59-year-old female with no medical history was received in our clinic for painful swelling on the right mandible. On clinical examination, we noticed a facial asymmetry caused by the swelling and bone exposure with pus on the right mandibular ridge. The panoramic radiography showed right and left posterior mandibular opacities. On the cone beam reconstructions, we noted a hyperdense posterior right mandibular image surrounded by a hypodense border and a hyperdense posterior left mandibular image surrounded by a hypodense border, in contact with the apices of tooth 36. Based on the clinical, radiographic and pathological findings, the present case was diagnosed as mandibular actinomyces osteitis associated with florid cemento-osseous dysplasia. The treatment consisted of surgical excision of the lesion, filling of the defect with PRF and prescription of antibiotics. Conclusion: Despite its rarity, practitioners should be aware of the possibility of the coexistence of these two entities simultaneously. Thus, they can initiate the appropriate treatment.

Wrist arthrodesis following resection of recurrent giant cell tumor of distal end of radius: A case report

The recurrence rate of giant cell tumor (GCT) of bone is 20%. GCT of bone is an aggressive and potentially malignant lesion, and variable clinical behaviour. The distal femur and proximal tibia are the most common sites, accounting for 50% of all GCT of bone, followed by the distal radius (10%). The prevalence of GCT peaks during the 3rd decade, with 80% of cases occurring between 20 and 50 years of age. Local recurrence and loss of joint function are still major problems following surgery The goals of treatment are to achieve satisfactory removal of the tumor, to decrease the chance of local recurrence, and to preserve as much wrist function as possible. Here we present a case of 32-year-old female patient presented with painful lump over right wrist joint since 2 months. Previously patient was surgically treated with intralesional curettage and illiac crest bone graft and bone cement for GCT of distal end of Radius 2 years back. Xray and Magnetic resonance imaging (MRI) showed a well-defined u expansile lytic soft tissue lesion which is homogenously enhanced involving medullary cavity with cortical erosion and extending into soft tissue plane. We performed wide resection of distal third radius and ulna using dorsal approach with radial strut graft and wrist arthrodesis. Functional outcome was evaluated using the modified Musculoskeletal Tumor Society scoring system. Grip strength was assessed using a dynamometer, and range of motion of the metacarpophalangeal joint was assessed using a goniometer.

A Unique Cause of Chronic Right Hip Pain and Unilateral Leg Swelling 10 Years Following Total Hip Arthroplasty

Abstract Patient is a 64-year-old female with a history of right total hip arthroplasty (THA) who presented with progressive painful right lower extremity edema and chronic groin pain for 2 years. A CT scan from October 2021 revealed an expanding, large iliopsoas bursal fluid collection that caused compression of the right common femoral artery and vein in June 2023. Further workup excluded deep venous thrombosis or infectious causes. Iliopsoas fluid collections can result from various conditions such as a rare complication of THA. This is likely due to mechanical irritation from the prosthetic components and was confirmed with resolution of symptoms after undergoing revision of THA in 2024. This case highlights iliopsoas hematoma as a rare but important consideration in patients with unilateral lower extremity edema following THA.

Painful swellings over the lumbar region in a dog.

Painful swellings over the lumbar region in a dog.

ACUTE TESTICULAR ISCHEMIA CAUSED BY INGUINAL HERNIATION WITH INCARCERATED LOOP OF SIGMOID COLON IN NEWBORN

The authors report a clinical case of a 14-day-old newborn with a left inguinal hernia with incarceration of the sigmoid loop associated with testicular ischemia, a clinical situation that posed some problems of diff erential diagnosis. The mother of the child was referred to the emergency department. Objective examination revealed hyperemia and edema of the left hemiscrotum, and on palpation there was a hard, irreducible, painful swelling. The child was urgently taken to surgery. On re-examination an incarcerated hernia was found with a viable sigmoid loop with moderate edematous changes. The testis showed obvious ischemic changes. With diffi culty, the sigmoid colon was reduced into the abdominal cavity, after observing the restoration of vascularization of the preserved testis. The postoperative result was positive and the child was discharged in satisfactory condition.

Abstract 4148074: Radial Artery Pseudoaneurysm Following Transradial Cardiac Catheterization: A Systematic Review and Case Report

Introduction/Background: Transradial cardiac catheterization (TRC) is recommended for patients with acute coronary syndrome over femoral artery catheterization. Randomized controlled trials show TRC has significantly lower rates of bleeding, vascular complications, and mortality in high-risk acute coronary syndrome patients. However, vascular complications like radial artery spasm, occlusion, arteriovenous fistula, perforation, and pseudoaneurysm (PSA) can still occur. Despite TRC's widespread adoption, recent data summarizing radial artery pseudoaneurysm post-TRC is lacking. Research Question/Hypothesis This review aims to identify at-risk patients, present a case of catheterization-related radial artery pseudoaneurysm, and provide diagnostic and management insights. We hypothesize that older patients with hypertension are at higher risk and that early detection and management are associated with low complication rates. Methods/Approach: Systematic searches were conducted in PubMed, Web of Science, EMBASE, and CINAHL databases. Two researchers independently selected articles, extracted data, and evaluated study quality on RA PSA post-TRC (2003–2023). A third reviewer resolved conflicts. The Joanna Briggs Institute (JBI) tool was used to evaluate bias risk. Additionally, a case report is presented. Results: From 3,262 records, 43 studies were selected, involving 67 patients (58.8% female, median age 73.5 years). Hypertension (39.5%) and atrial fibrillation (27.9%) were the most common comorbidities. Percutaneous interventions like stenting and angioplasty caused 58.1% of cases; diagnostic catheterizations accounted for 37.2%. Ultrasonography diagnosed 83.7% of cases. Symptoms appeared a few hours to four months post-TRC, with pulsatile mass (21.4%) and swelling (14.3%) being the most common, and pain and ecchymosis at 2.4% each. More than half of the patients (51.2%) required surgical intervention, but 66.7% recovered without deficits. Severe complications were rare, affecting fewer than 5%. Conclusions: A literature review of 43 articles with 67 patients suggests older female patients with hypertension may be more prone to radial artery pseudoaneurysm post-TRC. It typically presents as a pulsatile, painful swelling detectable by ultrasound. This complication precludes the use of the radial artery as a conduit for coronary artery bypass grafting. The review highlights the importance of vigilant post-catheterization monitoring to enable early detection and treatment.

Cutaneous manifestations and sequelae of Chikungunya fever: a single centre experience

Background: Chikungunya fever is a common viral illness in the tropical and subtropical areas. Various cutaneous manifestations can develop during the acute phase and post-febrile convalescent phase. Objective: To determine the frequency and types of cutaneous manifestations associated with chikungunya fever in acute and post-febrile phase. Methods: We conducted a prospective, observational study including 20 patients with laboratory-confirmed chikungunya fever. All the patients were followed up for 1 year to detect any cutaneous sequelae. Results: Pruritic maculopapular rash was the most common cutaneous manifestation during the acute febrile phase, noted in 60% of the patients. The rash usually appeared within 1–3 days of fever onset and spread in cephalo-caudal direction. Cutaneous hyperpigmentation was the most common dermatologic sequelae in the post-febrile period, occurring in 3 (15%) patients. In all patients, pigmentation appeared 3–4 weeks after resolution of fever, and started on the nose, gradually spreading to the forehead. The pigmentation improved significantly with topical hydroquinone after 4 weeks. Other additional manifestations of chikungunya fever included joint pain and joint swelling. None of our patients presented with mucosal or systemic involvement. Conclusion: Maculopapular skin rash was the most common manifestation during acute febrile phase of chikungunya fever, while cutaneous hyperpigmentation was the most common dermatologic sequelae after resolution of fever.

Clinical Outcomes and Safety Profile of a Dextranomer-Hyaluronic Acid Hybrid Filler: A Case Series Analysis.

The demand for aesthetic treatments targeting the middle and lower face is on the rise, especially because of changes in appearance associated with aging. This study aimed to assess the use of a hybrid filler for sculpting and contouring of the chin, jaw, and malar region. A retrospective analysis was performed on patients who underwent jaw and chin contouring and cheek augmentation using a hybrid filler (hyaluronic acid and dextranomer). The evaluation focused on the naturalness of appearance, enhancement in volume, and the durability of the results, employing a 5-point scale. Both patient satisfaction and physician evaluations were measured using the Likert scale and the Global Aesthetic Improvement Scale (GAIS), respectively. Follow-up with patients extended up to 6 months after treatment, during which any treatment-related adverse events (AEs) were meticulously recorded and analyzed. Nineteen patients participated in the study, receiving an average injection volume of 2.4 ± 0.9 mL to attain the desired outcomes. The evaluation of natural appearance, volumizing effects, and durability at the analyzed time point consistently scored above 4. All 19 patients' aesthetic improvement was evaluated as "very much improved" and "much improved", at the GAIS score. All patients report improvement in their appearance, with 89.5% rating it as "very much improved" or "much improved" on the Likert scale. Only expected AEs such as mild pain and lower swelling were registered. The hybrid filler proved effective and safe for facial contouring, with significant patient satisfaction and minimal adverse effects.

102. Surgical Treatment of Brachial Artery Aneurysm Associated qith Arteriovenous Shunt for Hemodialysis: Case Report

Introduction: A brachial artery aneurysm is a rare complication of an arteriovenous fistula (AVF) created for hemodialysis access. This report details the case of a patient with a brachial artery aneurysm associated with an AVF for hemodialysis, who underwent successful surgical treatment. Case: A 64-year-old female with CKD undergoing regular hemodialysis presented with a painful lump in her right arm one-week AVF installation. Her medical history included a left nephrectomy in 2022, previous failed AV fistula placement, and central dialysis line (CDL) insertion. The patient had a medical history significant for CKD requiring routine HD twice a week. Local examination of the patient's right arm revealed a mobile, painful lump, diagnosed as a brachial artery aneurysm, limiting arm movement. A chest X-ray showed cardiomegaly, thoracic spondylosis, and proper CDL positioning. Laboratory results were normal. The patient underwent surgical repair of the aneurysm and was hospitalized for three days postoperatively. Post-surgery treatment included analgesics, antibiotics, anticoagulation therapy, and outpatient clopidogrel. Conclusions: A brachial artery aneurysm is a rare complication of an AVF, posing risks of peripheral embolism and hand ischemia, and therefore requires surgical correction.

Facing a new reality: significant increase in necrotizing fasciitis in the post-covid era?

Necrotizing fasciitis (NF) is a rare, rapidly progressing soft tissue infection characterized by the widespread necrosis of fascial planes and surrounding tissues. We discuss four consecutive necrotizing fasciitis cases of the head and neck region, that accured in a time window of 6 months. Patient demographics, clinical features, laboratory analyses, imaging findings, surgical interventions, and outcome were collected, assessed and discussed. These findings were checked against recent epidemiological data of invasive Group A Streptococcus (iGAS) in Europe. Four patients (two males and two females) aged between 31 and 65 years were included. The most common presenting symptom was severe pain and facial swelling (100%), followed by fever (50%) and erythema (50%). All patients underwent emergency surgical debridement, and broad-spectrum antimicrobial therapy was initiated promptly. Streptococcus pyogenes was isolated in every patient. Three patients required multiple debridement procedures, and one case necessitated extensive neck resection due to the involvement of deeper structures. Overall, two patients recovered with no to minor residual deficits, one patient experienced persistent trismus and one patient passed away due to septic shock and multiorgan failure. Prevalence of iGAS infections have increased in European countries, therefore increased vigilance is recommended so that a quick diagnosis can be established and appropriate treatment can be administered to avoid serious morbidity and mortality.

Real-world outcomes in patients with hereditary angioedema prescribed lanadelumab versus other prophylaxis.

Background: Hereditary angioedema (HAE) is a rare genetic disorder characterized by painful, debilitating, and potentially fatal swelling attacks. Lanadelumab is approved as long-term prophylaxis (LTP) in patients with HAE. However, real-world data on LTP use in patients with HAE are limited. Objective: To describe clinical characteristics, attack history, and quality of life (QoL) of patients with HAE type I/II who were receiving lanadelumab or other LTPs. Methods: Data were drawn from the Adelphi HAE Disease Specific Program, a cross-sectional survey of HAE physicians conducted in the United States from July to November 2021. Physician-reported disease characteristics, HAE attack frequency, and QoL were compared among patients receiving lanadelumab or other LTPs for at least 12 months. Results: Physicians reported data for 144 patients, of whom 29 had received lanadelumab and 115 had received another prophylaxis for at least 12 months. The mean ± standard deviation number of attacks in the previous 12 months was lower among patients receiving lanadelumab than other LTPs (2.3 ± 3.1 versus 3.4 ± 2.8, respectively; p = 0.075). Although both groups had similar current disease activity and severity, more patients receiving lanadelumab versus other LTPs had high disease activity (51.7% versus 12.5%, respectively; p < 0.0001) and disease severity rated as severe (51.7% versus 16.1%, respectively; p = 0.0001) at diagnosis. Physicians reported that more patients who received lanadelumab had good or very good QoL (72.4%) than those receiving other LTPs (36.5%) (p = 0.003). Conclusion: Analysis of these findings suggests lower attack frequency, lower symptomatic impact, and better QoL in patients treated with lanadelumab than another prophylaxis in a real-world setting.